How to parent several cameras without adjusting one and interfering the others?
Parenting should not be used as an organization method for the outliner, it is a scene hierarchy system and has obvious implications in the 3D view as you've already experienced.

Use groups instead by grouping objects together and using the outliner in Groups mode so you can have objects in "categories" or "folders" without affecting their behavior.

A proper layer system is being worked on for the upcoming Blender 2.8 but it is still far off